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Structures and Phase Transitions in Pertechnetates
DOI:10.1021/acs.inorgchem.9b01257.png)
摘要
En 中文
The temperature dependence of the structures of four pertechnetates (ATcO(4) A = Ag, Tl, Rb, Cs) from 90 K to their melting points is described. Synchrotron X-ray diffraction measurements show that RbTcO4 undergoes a I4(1)/a to I4(1)/amd transition near 530 K that is associated with a change in the orientation of the TcO4- tetrahedra about the scheelite b axis. AgTcO4 also exhibits a tetragonal scheelite type structure, and this is retained between 90 and 750 K, above which it melted. CsTcO4 has an orthorhombic pseudo-scheelite structure at room temperature and this undergoes a first-order orthorhombic to tetragonal transformation (Pnma to I4(1)/a) near 430 K. TlTcO4 is isostructural with CsTcO4 at 90 K, but the orthorhombic to tetragonal transformation proceeds via an intermediate orthorhombic phase. The different behavior found here and described previously for the analogous Re oxide TlReO4 highlights the differences in the chemistry of these two systems.
Keyword:
X-RAY
CRYSTAL-STRUCTURE
AMMONIUM PERTECHNETATE
STRUCTURE REFINEMENT
NEUTRON-DIFFRACTION
THERMAL-EXPANSION
WASTE GLASS
LONE-PAIR
TECHNETIUM
RHENIUM
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期刊
IF:
4.7
论文数:
4.9W
被引数:
10.5W
机构
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INORGANIC CHEMISTRY
IF4.7

